Department of Psychology, San Diego State University, San Diego, CA 92182, USA.
Department of Neurosciences, University of California San Diego, San Diego, CA 92093, USA.
Cereb Cortex. 2021 Jan 5;31(2):1116-1130. doi: 10.1093/cercor/bhaa279.
Neuroimaging studies have revealed atypical activation during language and executive tasks in individuals with autism spectrum disorders (ASD). However, the spatiotemporal stages of processing associated with these dysfunctions remain poorly understood. Using an anatomically constrained magnetoencephalography approach, we examined event-related theta oscillations during a double-duty lexical decision task that combined demands on lexico-semantic processing and executive functions. Relative to typically developing peers, high-functioning adolescents with ASD had lower performance accuracy on trials engaging selective semantic retrieval and cognitive control. They showed an early overall theta increase in the left fusiform cortex followed by greater activity in the left-lateralized temporal (starting at ~250 ms) and frontal cortical areas (after ~450 ms) known to contribute to language processing. During response preparation and execution, the ASD group exhibited elevated theta in the anterior cingulate cortex, indicative of greater engagement of cognitive control. Simultaneously increased activity in the ipsilateral motor cortex may reflect a less lateralized and suboptimally organized motor circuitry. Spanning early sensory-specific and late response selection stages, the higher event-related theta responsivity in ASD may indicate compensatory recruitment to offset inefficient lexico-semantic retrieval under cognitively demanding conditions. Together, these findings provide further support for atypical language and executive functions in high-functioning ASD.
神经影像学研究表明，自闭症谱系障碍（ASD）个体在语言和执行任务期间存在异常激活。然而，与这些功能障碍相关的处理的时空阶段仍知之甚少。使用解剖约束性脑磁图方法，我们检查了在双重词汇决策任务期间与执行功能相关的事件相关θ振荡，该任务结合了词汇语义处理和执行功能的需求。与典型发育的同龄人相比，高功能 ASD 青少年在需要选择性语义检索和认知控制的试验中表现出较低的准确性。他们在左侧梭状回中表现出早期的整体θ增加，随后在左侧颞叶（从250ms 开始）和额叶皮质区域（在450ms 后）表现出更大的活动，这些区域已知与语言处理有关。在反应准备和执行期间，ASD 组在前扣带皮层中表现出升高的θ活动，表明认知控制的参与度更高。同侧运动皮层中同时增加的活动可能反映了运动回路的非侧化和次优组织。从早期的感觉特异性到后期的反应选择阶段，ASD 中的更高事件相关θ反应性可能表明在认知要求高的情况下，补偿性招募以抵消词汇语义检索效率低下。这些发现共同为高功能 ASD 中异常的语言和执行功能提供了进一步的支持。
